Introduction

Groundwater resources play a vital role in maintaining California's economic and environmental sustainability. During an average year, California's 515 alluvial groundwater basins and subbasins contribute approximately 38 percent toward the State's total water supply. During dry years, groundwater contributes up to 46 percent (or more) of the statewide annual supply, and serves as a critical buffer against the impacts of drought and climate change. Many municipal, agricultural, and disadvantaged communities rely on groundwater for up to 100 percent of their water supply needs. Groundwater extraction in excess of natural and managed recharge has caused historically-low groundwater elevations in many regions of California.

DWR has a long-standing history of collecting and analyzing groundwater data, investigating and reporting groundwater conditions, implementing local groundwater assistance grants, encouraging integrated water management, and providing the technical expertise needed to improve statewide groundwater management practices. In addition, DWR is responsible for implementing the Sustainable Groundwater Management Act (SGMA), the California Statewide Groundwater Elevation Monitoring (CASGEM) Program, and characterizing California's groundwater basins through updates to Bulletin 118.

To implement the increased responsibilities given to DWR by the 2014 Sustainable Groundwater Management Act (SGMA), DWR has expanded its existing local assistance programs in the Division of Integrated Regional Water Management (DIRWM) and has developed a Strategic Plan for the Sustainable Groundwater Management (SGM) Program. More info...

The Groundwater Information Center (GIC) is DWR’s portal for groundwater basics, technical groundwater information, groundwater management plans, water well basics, and statewide reports, maps, and figures. More info...

Senate Bill X7 6 (SBX7 6) in 2009 added provisions for groundwater monitoring to the California Water Code and authorized DWR to establish permanent and locally-managed groundwater elevation monitoring and reporting in all of California's 515 alluvial groundwater basins. To implement SBX7 6, DWR developed the CASGEM Program. More info...

The DWR has long recognized the need for collection, summary, and evaluation of groundwater data as essential tools in planning for the optimal use of the groundwater resource. An example of this is DWR’s Bulletin 118 series, which presents the results of groundwater basin evaluations and defines the boundaries of California’s 515 alluvial groundwater basins. More info...